The present invention relates to systems and methods for advanced medical devices, and in particular related to advanced cerebrospinal shunts, applications of shunt based therapies, and unique bioreactor designs that may mimic cerebrospinal environments with unprecedented accuracy. Such systems and methods provide for therapies that can treat disease states that were previously considered untreatable, increase the success of current cerebrospinal shunt treatments, and advance research into cerebrospinal pathology and physiology.
Shunts have longstanding been utilized by the medical community to move fluid from one part of the body to another. For example in ventriculoperitoneal shunting, one or more catheters are placed unto the vertical of a patient's brain, and extend down to the abdominal or chest cavity (often into the peritoneal cavity). A pressure valve or fluid pump may attach to the catheter(s) in order to allow fluids to exit the brain if the pressure rises above desired levels. Additionally, the valve prevents backflow of blood or other fluids into the brain. There are many valve designs that may accomplish various flow characteristics.
Typically shunt catheters are made of biocompatible materials, and are often selected based upon their final usage. Common shunt catheter materials include silicones, polyvinyl chloride (PVC), and latex rubber. Unfortunately, shunt failures may result from blockage of the proximal and/or distal catheters due to tissue ingrowth, cellular debris and clot, as well as shunt infection. Valve malfunctions are also possible. These frequent failures result in undue patient morbidity and mortality.
In response to these complications frequently associated with traditional shunts, additional and more exotic shunt materials have been experimented with. These newer shunt materials have been designed to include bioactive compounds, such as antimicrobial compounds, anticoagulation, and protein degradation compounds. Some shunts have also been proposed that include bioactivity, such as seeded shunts and enzymatically active shunts.
These newer shunt designs have come about for a variety of reasons, primarily related to buildup of protein, cellular debris, minerals, or other potential occlusions that negatively impact the flow characteristics of the shunt. While these advancements have been met with some degree of success, there is always a need for improved shunt designs that will provide long-term, cost effective, favorable flow characteristics in increasingly smaller luminal profiles.
Additionally, new interest has developed in utilizing shunts as not only a fluid pathway, but also as a broader therapeutic tool. This may include adding in properties that extend beyond mere fluid flow, but also increase patient health.
One area that has received particular interest is in cerebrospinal shunts. The diversion of cerebrospinal fluid from one location to another where it may be disposed is a well-known clinical strategy for a number of brain and spinal disorders, and is one of the most common neurosurgical procedures. Improving cerebrospinal shunt designs would have a marked impact upon a large number of patient's requiring this kind of procedure.
The cerebrospinal fluid flow has two components. A bulk flow from the production and absorption of cerebrospinal fluid and a pulsatile/oscillatory flow from influence of the cardiac cycle on the bulk flow. Also, there are respiratory and body positional influences on the cerebrospinal fluid flow.
With every heartbeat, a volume of blood enters the brain via the carotid and vertebral arteries, causing the brain to expand in the skull, which is a fixed container. This forces CSF out of the cranial cavity into the spinal subarachnoid reservoir, until diastole when the CSF is reversed. The CSF dampens the oscillations of the brain preventing injury. But in some CNS injury and disease the CSF production is diminished, so the pulse pressure (difference between systolic and diastolic pressures) can itself become an injurious process, the so-called pulse pressure encephalopathy.
It stands to reason that the long acting pressure changes along with ventricular lining and spinal central canal can injure the endothelium, which is comprised on ependymal cell and subependymal stem cells. Ependymal cells produce and process the CSF. Specialized ependymal cells in association with a capillary network are known as the choroid plexus. Damage to the ependyma and choroid can influence CSF production and reduce the dampening effect of cardiac pulsations, as well the clearance of toxic ions, proteins and metabolites.
Means for addressing the problems complacent with cerebrospinal shunts, replacement of CSF, and repair of cellular members that are involved in regulating the CSF environment could have significant clinical and research value.
It is therefore apparent that an urgent need exists for an improved cerebrospinal medical device that enables more efficient and longer lasting fluid flow properties in a cerebrospinal shunt, improved therapies, and enhanced research into cerebrospinal pathologies and treatments.